1. Field of the Invention
The present invention is directed, in part, to methods, apparatuses, and systems for providing emergency services in WiMAX networks.
2. Description of the Related Art
WiMAX, or Worldwide Interoperability for Microwave Access, is a technology that is standardized and certified by the WiMAX Forum, formed in June 2001 to promote conformance and interoperability of the IEEE 802.16 standard, officially known as WirelessMAN. The WiMAX Forum describes WiMAX as “a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL.” As such, WiMAX has the potential to replace many existing telecommunication infrastructures.
The fixed version of WiMAX (IEEE 802.16) is expected to provide broadband data services as an alternative to ADSL in countries where landline telephone networks are not well deployed, and the further evolved mobile version (IEEE802.16e) would complement the existing cellular systems (i.e. GSM, WCDMA, cdma200) and bring higher data throughput to subscribers than HSPA (High Speed Packet Access) in high mobility environments (up to 120 km/h).
While the IEEE standards specify L1/L2 air interface protocols between a Subscriber Station (SS) and Base Station (BS). (This disclosure alternatively refers to the user equipment as a subscriber station, mobile station, and/or terminal. The user equipment, subscriber station, mobile station, or terminal may be any kind of mobile or fixed user equipment or mobile station, such as a mobile phone, a fixed phone, a personal computer (PC), a laptop, a personal digital assistant (PDA) or the like). WiMAX Forum has tried to specify the end-to-end WiMAX network architectures and ensure interoperability between terminal products and network equipment manufactured by different terminal and infrastructure vendors.
WiMAX was originally developed as a data-centric wireless access and supports such typical packet data services as real-time polling and best effort. In addition to those services, WiMAX also supports Voice over Internet Protocol (VoIP) that transports VoIP data packets on a periodic basis. MAC (L2 protocol) plays a central role in negotiating Quality of Service (QoS) traffic parameters for VoIP and creating a service flow (hence, radio bearer) to transfer voice packets between the SS and BS.
Although the WiMAX system specifies a mechanism to offer voice services, its standards do not yet support emergency calls. However, support of emergency services in telecommunication systems is required by regulatory authorities in many markets, including the requirement of prioritized access to emergency centers for emergency calls. In large scale emergencies, wireless networks are likely to become congested with calls. As a result, calls to and from emergency response personnel may also be blocked. Therefore, wireless networks should possess the capability of providing several levels of priority for processing emergency calls in heavy network traffic.
In addition to the well known 911 emergency calling, wireless priority service (WPS) is a system in the United States that allows high-priority emergency telephone calls in congestion situations on wireless telephone networks for selected emergency response management personnel. This complements the Government Emergency Telecommunications Service (GETS), which allows such calls on landline networks. The service is overseen by the Federal Communications Commission and administered by the National Communications System in the Department of Homeland Security. WPS allows high-priority calls to overcome that congestion and receive priority. The system is authorized only for use by National Security and Emergency Preparedness personnel, classified into five categories: Executive leadership and policy makers (e.g. the president of the United States and members of congress); Disaster response/military command and control; Public health, safety, and law enforcement command; Public services/utilities and public welfare; and Disaster recovery.
Telecommunications Service Priority (TSP) is the highest level of priority which provides guaranteed priority for restoration of telecommunications services when service providers' resources are overextended and provides priority provisioning for wireline telecommunications services when the normal provider processes will not meet the need. In view of the importance of providing support for emergency services, there is a need for WiMAX networks to also provide the mechanisms necessary to support emergency call handling so that users can easily contact public safety departments with a WiMAX-capable terminal. WiMAX Forum SPWG requires multiple priority levels for flows related to Location Based Services (LBS). This will enable the QoS differentiation between LBS service flows. Therefore, if contention for resources arises, a higher-priority LBS flow or an Emergency Service shall have precedence over lower-priority flows.